Features of erosion


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Features of erosion

  1. 1. Features Of ErosionBy Jesse, Abdullahi, John, Nderitu and Angela. 1
  2. 2. Waterfalls• Waterfalls are usually formed when a river moves over resistant bedrock and erodes it slowly while downstream it happens faster.• As this happens material is plucked from a river bed which causes the waterfall to carve deeper into the riverbed and recede upstream• part of the bedrock (hard rock) will later break off, exposing the soft rock, and form a waterfall.• The rest is in the diagram on your right 6/6/12 Group Y 2
  3. 3. OX BOW LAKES• An ox bow lake is a U - shaped water body or meander that is cut of by erosion to form a lake.• They are formed when a river has a very curve us meander, which is nearly meeting the other side of the river.• Due to erosion and deposition the neck of the meander becomes very narrow which allows water to pass straight, flowing past the old meander.• Deposition then occurs, sealing of the meander.• The deposition then totally covers up the meander so no more water can pass.• Over time the closed meander completely cuts of from the rest of the river.• The end result is a straight river separated from a curved C-shaped lake.6/6/12 Group Y 3
  4. 4. OX BOW LAKES6/6/12 Group Y 4
  5. 5. V-shaped valleys.• In the upper course of a river, water flows at a high speed through a narrow channel with a steep gradient.• As it does, so it cuts downwards.• This vertical erosion results in a number of distinctive landforms including, the steep sloped v- shaped-valleys• Through this the river flows in its upper course.6/6/12 Group Y 5
  6. 6. Formation of v-shaped-valleys.• Vertical erosion leads to the development of steep sided, narrow valleys shaped like the letter V.• The valley sides are steep due to the soil and loose rock being washed downhill following periods of heavy rainfall.• The material is then added to the load of the river.• The river itself forced to wind its way through protruding hillsides.• These hillsides known as interlocking spurs restrict the view up or down the valley.6/6/12 Group Y 6
  7. 7. RAPIDS• A river rapid is a section of a river with a steep gradient, which cases an increase in the water velocity and the turbulence.• A rapid is caused by the river becoming shallower and having some materials, like rocks, to be exposed above the flow surface.• In rapids, water turns white because flowing water splashes over and around the rocks, and air bubbles mix with them.• This colour is normally called “White water”.• Rapids normally occur when the river bed is highly resistant to erosion.6/6/12 Group Y 7
  8. 8. Rapids• Rapids are categorized into several classes:• Class 1- This is when the river has small waves in fast flowing water and has very few obstacles, e.g. rocks.• Class 2- When the river has wide channels and rapids , without many turns and obstacles.• Class 3- This class has strong currents with many obstacles in the river.• Class 4- Powerful rapids with big waves• Class 5-Very violent and dangerous rapids with tight turns• Class 6- This last stage is the most violent and strong. This rapid can cause death easily. 6/6/12 Group Y 8
  9. 9. Rapids• Many people use these river rapids to have fun.• Rafting, is a sport which requires rapids.• Rafting courses are also classified using these rapid classes.6/6/12 Group Y 9